Machine Design
The Machine
Poster
Video
Full Project Documentation:
Fab Academy Machine Week 2025 – Devanshi Mengar
During Machine Week at FabLab RIIDL, our team of five set out to build a walking robot entirely from scratch — no kits, no blueprints, just mechanical brainpower and laser cutters.
I was responsible for Leg mechanism:
Designing the leg mechanism that would literally make the robot walk.
The Spark:
Our mentors Jesal Sir and Pranav Sir introduced us to the captivating world of Theo Jansen’s mechanical creatures. That initial discussion lit the fuse.
From there, I explored further through the Expo21xx reference, which breaks down the exact linkage dimensions and walking cycle of the Strandbeest mechanism.
That’s when the deep dive began.
understanding the Motion
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Extracted 12 key linkages with accurate lengths
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Identified 3 key fixed pivot points
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Created a two-triangle framework housing:
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An upper and lower 4-bar linkage
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A central parallel motion coupler
This formed the skeletal blueprint of our kinetic leg.
First Functional Prototype
Before worrying about looks, I tested the pure mechanics.
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Laser-cut basic linkages
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Assembled them manually
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Confirmed that the stride path worked exactly like Theo Jansen’s walking loop
It wasn’t pretty yet — but it walked. That was the “yes!” moment.
From Rough Cut to Refined Motion
Now it was time to finesse:
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In Fusion 360, I refined the sketches and crafted a signature triangular leg shape
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Optimized the sketches for mirroring, so I only had to design one half of the mechanism
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Created precision slots, mounting holes, and pivot joints
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Maintained mechanical constraints to preserve natural motion
Assembly & Final Sync
As a team, we came together to assemble the full bot. I led:
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Alignment of the links and pivots
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Final gear fitting
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Ensuring smooth, synced bilateral leg motion
Key Takeaways
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Mechanics is movement — Geometry can create life-like motion
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Mentorship matters — A single idea from mentors can spark the whole system
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Prototyping early avoids late-night disasters
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Design with mirroring in mind to save fabrication time
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